Automatic damper



July 8,1930. H. E. LAKE AUTOMATIC DAMPER 1928 2 Sheets-Sheet 1 Filed March 10 a avwemtoz Q? July 8, 1930. K 1,770,339

AUTOMATIQ DAMPER Filed March 10, 1928 2 Sheets-Sheet 2 Patented July 8, i936 HARRY E. LAKE, OF NEW YORK, .l\T..Y., ASSIGNOR T0 PREFERRED UTILITIES MANU FACTURING CORPORATION, OF NEW, YORK, Y., A CORPORATIONOF DELAWARE AUTOMATIC DAMPER Application filed March 10, 1928. Serial No. 260,745.

My invention consists in the novel features hereinafter described, reference being had to the accompanying drawings which show one embodiment of my .invention selected by me for purposes of illustration, and'the said the parts of the adjusting means detached invention is fully disclosed in the following description and claims.

The object of my inventlon is to provide an automatic damper unlt for use 111 a stack or smoke pipe through which heated'gaseous products are conveyed, and adapted espe cially for use in connection with heating furnaces and especially with those in which the heat is supplied by means of an oil or gas burner, although it may be employed in any connection in which its use is desirable. The damper is operated by a thermostatic member, preferably in the form of a coil or helix, one end of which is connected with the damper and the other end is connected with a relief spring, so that when the damper is closed and the thermostatic member continues to operate underhigh'er temperature than the closing temperature, the strain on the thermostatic member is taken by the relief spring, and distortion and injury to the thermostatic member is prevented. The device is also provided with means for readiiy adjusting the position ofthe damper in its closed and open positions, and means are provided for sealing. these adjusting means,

so that their positions cannot be changed without breaking the seal, thus preventing the damper adjustments from beingchanged by unskilled persons who may be in charge of the heating plantand who might adjust the damper to an uneconomic position, or

even to one involving danger to the plant,

or the occupants of the building in which it is located. The damper unit also includes a casing provided with means for suspending it when used in connection with a horizontal stack, to relieve the stack from the weight of the damper unit.

Referring to the accompanying drawings,

Fig. 1 is a top plan view of my improved automatic damper unit showing the damper adjusting and sealing means.

1* ig. 2 is a view taken from-the opposite side and showing the relief spring for the thermostatic element. i

Fig. 3 represents a horizontal sectional View of the device.

Fig. 4 is a detail perspective view showing from each other.

Fig. 5 is an enlarged elevation of the adjusting means. i

Fig. 6 is an enlarged sectional View of the trated in the accompanyingdrawings, 1, rep-- resents the damper casing or body, which is of cylindrical form, and provided at its opposite ends with sleeve portions, 2 and 3, re-

spectively, to receive the adjacent sections of the stack. In this instance the sleeve, 2, is of smaller diameter than the sleeve, 8, and is. intended to be fitted into one of the pipe sections, as indicated in dotted lines in Fig. 1, for example, the sleeve, 3, having its internal diameter of such size as to permit the adjacent section of the'staclr to be inserted therein, as also indicated indotted lines in Fig. 1. Thecasing,'l, is provided with a shaft extending transversely through the same and indicated at 4:, tosupport the rotary damper, 5, which is preferably formed of thin cast metal, which may be reinforced by suitable webs, 5", and provided at one point with a bearing lug, 6, engaging the shaft, 4;, adjacent to one end of the shaft, the damper being provided at its opposite side or edge with a sleeve, 7, engagingthe shaft, 4, and extending longitudinallythere of through a bearing sleeve, 8, fitted in an aperture in the casing and projecting beyond the outer surface of the same. The opposite side of the casing is'provided with a bearing sleeve, 9, whichieng'ages and supports the shaft, 4. While I prefer to form the damper, 5, of cast metal with the bearing lug, 6, and sleeve, 7, cast integrally therewith it is entirely obvious that the damper might be formed of sheet metal and that-the bearing inc lug and sleeve may be in such case formed separately and secured to the damper in any usual or desired manner. The bearing sleeve, 8, as before stated extends beyond the outer surface of the casing, 1, and forms the bearing support for the adjustable stop plates hereinafter described, while the sleeve, 7, of the damper projects beyond the outer end of the bearing sleeve, 8, and is provided with a movable damper stop lug, 10, which in this instance is carried on a collar, 11, mounted on the outer end of the sleeve, 7, and secured thereto by a set screw, 12. Upon the projecting portion of the stationary bearing sleeve, 8, are mounted a pair of superimposed adjust-able stop plates, 13 and 23, shown detached in Fig. The plate, 23, is provided with a central aperture, 24, to engage the sleeve 8, and a stop lug, 25, to engage the face, 10, of the damper stop lug, 10, and determine the open position of the damper. The plate, 23, is also provided with a curved slot 26, which is co-axial with the aperture, 24, and the said plate is also provided with a sealing lug, 27, perforated as indicated at 28, for the passage of a sealing wire therethrough. The plate, 13, is also provided with an aperture in, for engaging the stationary sleeve, 8, and stop lug indicated at 15, for engaging a projection, 10", of the damper stop lug, 10, and a curved slot, 16, co-axial with the aperture, 14:.

The casing, 1, is provided adjacent to the stationary bearing sleeve, 8, with an exterior flattened portion, 1 The plates, 23 and 13, are placed in position with their apertures, 24, and 14, respectively, engaging the bearing sleeve, 8, the plate, 23, engaging said flattened portion of the casing, and the plates are secured in position with respect to the casing and adjustable with respect to the damper stop lug, 10, by means of a single screw, i dicated at 30, which passes through the curved slots, 16, and 26, of the adjustable stop plates, and is threaded into an aperture in the flattened portion, 1, of the casing. The plates are so formed that their slots, 16, and 26, extend in opposite directions from the screw, 30, as clearly shown in Fig. 5 for example and when the adjacent ends of the slots are both in engagement with the screw, as shown in that figure, the damper will have its greatest range of movement, which is approximately 90, the engagement of the damper stop lug, 10, with the stop lug, 25, determining the position of the damper when in open position, and the engagement of the damper stop lug, l0,with the stop, 15, determining the position of the damper when in closed position. By loosening the set screw, 30, and turning the plates, 13 and 23, respectively, in the directions indicated by the arrows in Fig. 5, as permitted by their respective slots, the range of movement of the damper from open to closed position as permitted by the stops, 25

and 15, respectively, can be adjusted in accordance with the requirements of the installation with which the damper is employed. /Vhen the desired range of movement from open to closed position has been determined, the set screw, 30, will be set up tight, thereby simultaneously locking both of said plates, 13 and 23, with respect to each other and to the casing, and holding the sto )S, 25 and 15, in fixed relation with each other and with the casing.

This construction is eirtren y at the same time is strong, i cut and very easily adjusted toaccommodate exactly the desired range of movement of the damper, and to arrest the dam er in exactly the'desired closed or par ially closed or open or partially open positions to which it is moved automatically, as hereinaft r described, by the thermostatic member or element. In some instances, and especially in the operation of furnaces fired with oil or gas under forced draft, an improper adjustment of the damper would tend to decrease the eli'ciency of the furnace and m giit esult in creating a dangerous condition, and t is, tl erefore, desirable to provi le mean or preventing unskilled persons from disturbing the adji ment of the damper afte they h ve been accurately determined by an expert der whose supervision such installations are ordinarily made. I, therefore provide a very simple and efiective means preventing any change in the adjustment of the plates, 13 and 23, after they have been set, and the screw, 30, tightly screwed in. In this instance I have shown the plate, 23, proJidc-d in the sealing lug, 2?,- b l l or referred to, and i also provide a cap, 31, adapted to fit 0 er the screw, 30, the cap and the h ad of the screw being provided with tering transverse apertures, 32 and 33, respectively, and a sealing wire, indicated at passed through the registering apertures, in the screw, 30, and cap, 31, and through the sealing aperture, 28, in the lug, 27, and the ends of the wire are connected by the usual lead seal, indicat d a" 35. The cap prevents the t screw by a screw driver and the sealing wire the cap, so that the dev with, or the adjust changed, without e f the sealing wire or destroying t -e se and the device is, herefore, protected against injudicious ma tions by unskilled persons who may be to porarily in charge of re p The shaft 4:, which carries the mp2 provided at one end with a collar, indi ated at 36, secured thereto by a screw for preventing the longitudinal movement of the shaft, and the opposite end of the shaft provided with a spring housing, within which is a block, 38, secured to the ca ing, 1, by screws, 39, and provided with means, as

regis L Q 1 1 ice cannot be tampered tae damper subjected to hi 'h temperature its expansion a notched portioinO, for receiving one end of a relief springflll, the other'end of which is secured to the spring housing,'as at 42. lhis relief spring holds the shaft normally from movement in a rotary direction.

Thethermostatic member is indicated at 43, and comprises a coil or helix of suitable material, as for example parallel strips of metals having different co-efficients of expansion, or any other desired material, one end of the coil or helix, as at 44;, being connected with the shaft, and the other end, as at 4-5, being connected to the damper at a point distant from its axis of rotation, and the helix being so constructed and arranged that when will effect the rotation of the damper'in a direction toward its closed position. The damper stop lug, 10, is secured to the shaft, 4, in such position that when its face, 10, is in contact with the stop lug, 25, on the plate, 23, and the end of the slot, 26, indicated at 00, is in engagement with the screw, indicated at 30,- the thermostatic member will hold the damper in its open position when cold, and

the roducts of combustion passing through the damper casing and stack become more and more highly heated, the thermostat ic member will move the damper towardits closed position until the projection, 10, on the damper stop lug engages the stop lug, 15, on the plate, 18. As before stated, the plates, 13 and 23, are adjusted withrespect to each other and the casing, so as to regulatethe range of movement which will be imparted to the damper by the thermostatic member. it will also be understood that when the damper is in the so-called closed position, it

does not entirely close under any circum stances the aperture within the damper casing, 1, and as isusual in all dampers, the damper, 5, is provided with a central aperture, indicated at 5 to provide for a portion at least of he minimum draft permitted, As a matter of fact, T prefer that when the damper is in the ultimate closed position permitted by the adjustment of plates, and 26, it is not seated definitely so as to prevent the passage of air around it, and to this end the damper stop lug, 10, is preferably provided with the projection, 10, previouslyreferred to, which will engage the stop lug, 15, on the plate 13, before the damper reaches the completely closed position, and thus permit the passage of a certain amount of air around the edges of the damper. This permits me to make the central aperture, 5, smaller than would otherwise be'necessary, and adds strength to the damper itself.

As the products of combustion passing through the stack may at times exceed the temperature at Which the damper is arrested in its closed position, the increased heat imparted to the thermostatic element after the arresting of the damper would have a tendamount of draft.

site direction on'the relief spring.

ency to distortthe thermostatic member and bendit out of normal condition and adjustment so as to interfere withits accurate operation thereafter. In order toovercome this difiiculty the relief spring, 41, is provided and is coiled in such a direction that after the thermostatic member, l3, has moved the damper to its closed position, the increase in temperature of the products of combus- 7 tion passing through the damper cas ng will case after the movement of the damper is,

stopped, the further action of the thermo- S'tQtlC member would react upon the and tend to rotate it in a direction to unw nd the reliefspring. The reliefspring, therefore,

compensates for the increased movement of the thermostatic member, 43, beyond that permitted by the controlling stop mechanism for the damper, and preserves the thermostatic member from injury.

- The relief'spring also serves another important purpose in delaying theclosing of the damper when the fire is first lighted, until the stack has attained'a sufficiently high temperature to insure and maintain" a desired It is to be noted that the thermostatic element is interposed between the relief spring and the damper and acts in one direction on the damper and inthe oppo- It will lso be obvious that when the fire is'started the thermostatic element will heat up more rapidly than the stack. In my construction as the thermostatic element begins to heat up it reacts onthe relief spring until the latter attains a resistance equal to turning resistance of the damper, after which the chef spring stops and the.

movement of the r damper begins to move toward the closed position; This retards the closing of the damper and permits the stack to heat up to a point where a sufficient draft is insured and maintained before the damper is closed.

Asshown in Fig. 3, the housing, 37, carrying.

one end of the relief spring issecured to the shaft, l, by a set screw, 37, and this initial tension of the relief spring may be adjust ed by rotating the housing with respect to the shaft and securing it in adjusted position by the set sorew,3? thus adjusting the relief spring to secure the desired retardation of the closlng movement of the damper.

ltwill be seen that the automatic damper unit will hold the damper 1n the proper open position for starting the heating apparatus with which it is used, and may be set for any desired maximum opening in the cold position, and for any maximum closed position in the hot position, so that the desired amount of draft may be had at the time of starting the plant and will be automatically reduced as low as desired when the heating plant is in full operation, the thermostatic member being protected against injurious distortion from'high temperature when the damper is in the closed position and tie adjusting de vices for the damper being sealed against injudicious manipulation by lmsirilled persons.

I conveniently provide the casing, 1, with attaching means such as the screw eyes, indicated at 50, disposed at opposite points 90 remote from the axis of the damper shaft, 4, which maybe employed to support the clamper from a suitable stationary support above the same, when it is used in a horizontal stack or pipe, for the purpose of relieving the stack itsel of the weight of the damper casing and attaching p lVhen the damper unitis used in vertical stack, it will naturally be supp rted from the pipe section below the damper unit, but even such position the eyes, 50, may be connected with supporting means connected to a stationary part, in order to relieve the pipe section from an undue amount of the w ight of the unit, if desired. It will be noted that the temperature adjusting stop mechanism is located or rior to the casing, where it can be readi y adjusted while the heating plant is in operation, to secure the desired operation of the damper and the correct range of movement which is to be permitted to the damper in order to secure the mosteiiicient and safe operation of the plant. t will also be noted that the relief spring is likewise located outside of the damper casing wncre it is protected from the high temperature of the products of combustion and the heat transmitted to it through the shaft and easing may be readily radiated to the atmosphere, thus preventing it from becoming overheated to a degree which might affect its temper.

What I claim and desire to secure by Letters Patent is 1. The combination with a damper casing, of a shaft rotatably mounted therein, a damper pivotally mounted on said shaft, a helical thermostatic member having one end connected with the shaft and the other end con nected with the damper, a relief spring casing secured to said shaft and located outside of said damper casing, a relief spring in said casing, having one end see red thereto and the other end secured to the damper casing, and means for arresting the movement of the damper under the action of said thermostatic member, said relief spring being constructed to no 'mally hold the shaft in a predetermined position, but permitting the shaft to rotate under the action of the thermostatic memher, after the movement of the damper is arrested, to prevent injury to the thermostatic member.

2. The combination with a casing, of a damper rotatably mounted there'n, an means for impartin rotary movement to said damper in opposite directions, a pair of superimposed plates, adj ustablc with respect to each other and to the casing, a stop on one of said plates for linn ig the movement of the damper in one direction, a stop on the other plate for limiting the movement of the damper in the opposite direction, a stop socured to the damper and movable between said plate stops, and means 1 securing said lat-es '11 their adjusted positions.

3. combination with casi damper rotatably mon 1 means for impa ng rotary movement to saic damper in opposite directions, a damper stop located outside of said casmg an secured to said damper, a pair of superimposed plates, novable with respect to each other and with respect to the casing coarzially with the dampor and located on the outside of said casing, one of said plates being provided with a stop to engage the damper stop to limi the closing movement of the damper, and the other of said plates provided with a stop to eno go the damper stop to he on iiinlii einent of the dam aer, and means fcuring said pla es in their adjusted positions.

l. The com? nation with a casing, of a damper rotatably mounted therein, a ill means for imparting rotar movement to sait damper in opposite directions, damper stop located outside of said casing and secured to said damper, a pair of superimposed plates, movable with respect to each other and with respect to the casing coaXially with the dampor and located on the outside of said casing, one of said plates beii L provided with a stop to the damper stop to limit t e closing movement of the damper, and the other of said plates being provided w' stoo to 7 ,r i the damper or stop to in .1 the opening movement the damper, and cool. of said plates being provioed with a slot curved coa ially with the of tie curing means exten ing thio' m ru L r w v enga ing the casin ior uQltLlu sa P: in the1r adpisted position.

5. The combination with a casing, of a damper rotatably mounted therein, and means for imparting rotary movement to said damper in opposite directions, a damper stop located outside of said casing ant. secured to said damper, a pair of superimposed plates, movable with respect to each other and with respect to the casing coaxially with the damper and located on the outside of said casing, one of said plates being provided with a stop to engage the damper stop to limit the closing movement of the damper, and the other of said plates being provided with stop to engage the damper stop to limitthe opening movement of the damper, said plates being provided with segmental slots having their edges coaxial with the axis of the damper, and at the same distance therefrom and a set screw extending throughlthe said slots of both plates for securing said plates in adjusted position,

6. The combination with a casing, of a damper rotatably mounted therein, and means for imparting rotary movement to said damper in opposite directions, a damper stop located outside of said casing and secured to said damper,'a pair of superimposed plates, movable with respect to each other and with respect to the casing coaxially with the damper and located on the outside of said casing, one of said plates being provided with a stop to engage the, damper stop to limit the closing movement of the damper, and the other of said plates being pro vided with a stop to engage the damper stop to limit the opening movement of the damper, means for securing said plates in adjusted positions, and-sealing means for preventing the readjustment of said plates, and the stops carried thereby.

7. The combination 'with a casing, of a damper rotatably mounted therein, and means for impartingrotary movement to said damper in opposite directions, a damper stop located outside of said casing and secured to said damper, a pair of superimposed plates, movable with respect ,to each other and with respect to the casing coaxially with the damp er and located on the outside of said casing, one of said plates being provided with a stop to engage the damper stop to limit the'closing movement of the damper, and the other of saidplates being provided with a stop to engage the damper stop to limit the opening movement of the damper, said'plates being provided with segmental slots having their edges coaxial with the axis of the damper, and at the same distance therefrom, a set screw extending through the slots of both plates for securing them in adjusted position, and sealing means including a cap for enclosing the head of said screw, said head and cap having registering apertures, a sealing Wire, and a seal for connecting the end portions of said wire. i

8. The combination with'a damper casing, provided with opposite bearing apertures, of a shaft extending through said apertures, a

damper pivotally mounted on said shaft and provided with a sleeve extending through'one of said apertures, a damper stop carrled by said sleeve, a pair of superimposed stop plates coaxial with the said shaft located on the extenor of the casing, and each provided with a stop to engage said damper stop, said plates being ad ustable to limit-the range of movement of the damper, and being provided wlth curved slots coaxial with the shaft and adapted-to overlap, a set screw engaging the slots of both plates and secured to the casing to lock the plates in adjusted position, a thermostatic member having one end connected to said shaft, and the other connected to the damper, and ajrelief spring operatively connected with said shaft for holding it normally in a, predetermined position but permitting rotation of the shaft under the action of the thermostatic member to prevent injury thereto.

9; The combination with a damper casing,

provided with opposite bearing apertures, of a shaft extending through said apertures, a damper pivotally mounted on said shaft and provided with a sleeve extending-through one of said apertures, a damper stop carried by said sleeve, a pair of superimposed stop plates coaxial withthe saidshaft located on the exterior of the casing, and each provided with a stop to engagesaid damper stop, said plates being adjustable to limit the range of movement of the damper, and being provided with curved slots coaxial With'tll shaft and adapted to overlap, a set screwengaging the slots of both plates and secured to the casing to lock the plates in adjusted position, a. the r-- terposed between one end of the thermostatic element and the part operatively connected with said end, and capable ofyielding under the reaction of the thermostatic element until said relief device attains a resistance equal to the turning resistance of the damper.

11. The combination with a casing, and

-a damper pivotally supported therein, of a thermostaticv element located within the casing'and having one end operatively connected with the damper, a resilient relief device located outside of. said casing and operatively connected with therother end of said thermostatic element, and with a stationary. part of the casing, and capable ofyielding under the reaction. of the thermostatic element until itattains a resistance equal to the turning resistance of the damper, and means for limiting the movement of the damper with respect to the casing. v

f 12. The combination with a cylindrical casing, for the passage of heated products of combustion therethrough, a revoluble shaft extending through said casing, a damper ro- 5 tatably mounted with respect tosaidshaft,

a coil thermostatic element comprising united strips of metals having different co-eificients of expansion, one end of said element being connected to the damper and the other end to said shaft, a coiled relief spring located outside of said casing, and having one end connected with said shaft and the other end connected with a fixed part of the casing, said relief spring being capable of yielding under the reaction of the thermostatic element until it attains a resistance equal to the turning resistance of the damper, and stops for limiting the movement of the damper.

13. The combination with a casing, and a damper pivotally supported therein, of a thermostatic element located within the casing and having one end operatively connected with the damper, a resilient relief device located outside of'said casing and operatively connected with the other end of said thermostatic element, and with a stationary part of the casing, and capable of yielding under the reaction of the thermostatic element until it attains a resistance equal to the turning resistance oi the damper, means for limiting the movement of the damper with respectto the casing, and means for adjusting the initial resistance of the said resistance device to vary the temperature at which the damper Will be moved and the temperature at which it will be arrested. v

In testimony whereof I affix my signature.

HARRY E. LAKE. 

